import java.awt.Color; //use Color class
import uwcse.graphics.*;

/** A class to display and action a traffic light */
public class TrafficLight {

	// instance fields
	private GWindow window;
	private Oval red;
	private Oval yellow;
	private Oval green;

	/**
	 * Construct the traffic light
	 */
	public TrafficLight() {
		// Window: 170x250 with the "Traffic light" title
		window = new GWindow("Traffic light", 170, 250);

		// Enclose the circles in a box
		Rectangle r = new Rectangle(50, 50, 50, 150, Color.black, true);
		window.add(r);

		// Circles of the traffic light
		// all in a vertical line with a diameter of 50 pixels
		// initially the light is green
		red = new Oval(50, 50, 50, 50, Color.red, false);
		window.add(red);
		yellow = new Oval(50, 100, 50, 50, Color.yellow, false);
		window.add(yellow);
		green = new Oval(50, 150, 50, 50, Color.green, true);
		window.add(green);

		// show the traffic light
		window.doRepaint();
	}

	/**
	 * Set the traffic light to green
	 */
	public void setToGreen() {
		// remove all circles and create new ones with the right fill
		window.remove(red);
		window.remove(yellow);
		window.remove(green);
		red = new Oval(50, 50, 50, 50, Color.red, false);
		window.add(red);
		yellow = new Oval(50, 100, 50, 50, Color.yellow, false);
		window.add(yellow);
		green = new Oval(50, 150, 50, 50, Color.green, true);
		window.add(green);
		// Show it
		window.doRepaint();
	}

	/**
	 * Set the traffic light to yellow
	 */
	public void setToYellow() {
		// remove all circles and create new ones with the right fill
		window.remove(red);
		window.remove(yellow);
		window.remove(green);
		red = new Oval(50, 50, 50, 50, Color.red, false);
		window.add(red);
		yellow = new Oval(50, 100, 50, 50, Color.yellow, true);
		window.add(yellow);
		green = new Oval(50, 150, 50, 50, Color.green, false);
		window.add(green);
		// Show it
		window.doRepaint();
		// Exit the application when closing the window
		window.setExitOnClose();
	}

	/**
	 * Set the traffic light to red
	 */
	public void setToRed() {
		// remove all circles and create new ones with the right fill
		window.remove(red);
		window.remove(yellow);
		window.remove(green);
		red = new Oval(50, 50, 50, 50, Color.red, true);
		window.add(red);
		yellow = new Oval(50, 100, 50, 50, Color.yellow, false);
		window.add(yellow);
		green = new Oval(50, 150, 50, 50, Color.green, false);
		window.add(green);
		// Show it
		window.doRepaint();
	}

	/**
	 * Entry point of the program
	 */
	public static void main(String[] args) {
		new TrafficLight();
	}

}